Protected blade



A41111122, 1941. J, MUROS 2,239,536

PROTECTED BLADE Filedloet. 12, 1959 NVENTR Byfym @uw 1 Patented. Apr. 22, 1941 2,239,536 PROTECTED BLADE Joseph Muros, Cambridge, Mass., asslgnor to Gillette Safety Razor Company, Boston, Mass., a

corporation of Delaware Application October 12, 1939, Serial No. 299,120

2 Claims.

Manufacturers of dne edged blades by modern methods of production are able to provide extremely thin sharp cutting edges, but a necessary concomitant of lthe characteristics of this extreme sharpness is delicacy of structure in the cutting edge itself. It is accordingly a serious problem to protect the cutting edges of such blades from corrosion and from mechanical damage during the process of distribution. It is the practice to protect the body of safety razor blades by a coating of impervious lacquer and, while this is entirely effective in protecting the body of the blade, it does not extend to the bright metal of the bevelled edge which islaid bare by the grinding, stropping and honing operations. Such blades are, therefore, exposed to atmospheric conditions in their most vital parts and a relatively slight amount of rust formed on the cutting edge due to atmospheric moisture veryl seriously impairs the ilne shaving characteristics of the blade. The danger of mechanical damage is also ever present, since the mere contact of the ne sharp edge with wrapping material or with any part of the razor tends to blunt the extreme edge thereof.

The object of the present inventionas before intimated, is to protect effectively fine edge blades against these dangers and to accomplish certain other very desirable objects which will be hereinafter referred to. I have discovered that all these ends may be achieved by surrounding the bevelled or sharpened edges of the blades by a sheath or bead which may be removably attached to the blade as soon as its cutting edge has been completed and removed only after the blade has been safely located in the razor or other holder in which it is to be used.

The protecting sheath or bead may advantageously comprise any readily softenable or soluble material which is otherwise qualied for the desired protective functions. I have in mind employing a gelatin solution of the proper consistency to form a rounded bead when the sharp edge of a blade Withdrawn after being dipped therein and which will solidify almost immediately when exposed to the atmosphere or a drying oven. A particular advantage of using such material as gelatin for a protective bead or sheath is that it is' very readily soluble in hotl or cold water so that the user has only to clamp his protected blade in shaving position in his safety razor and then by rinsing it in Water, either hot or cold, can instantly remove the protecting bead exposing the fine sharp edge of the blade in the same perfect condition in which it came from the sharpening instrumentalities of the manufacturer. Other materials such as melted sugar, tapioca, beeswax, parafiin, etc., or combinations of these and other materials may be employed. It is contemplated that a formula may be selected that will produce a sheath which is transparent or opaque, colored or colorless as desired. All of these have the desired properties of adhesiveness facilitating attachment; they are adequate to protect the edge against corrosion; they have sufllcient stillness when solidified to protect the edge against damage; and finally they are all softenable by heat or soluble in water.

In addition to the advantages above discussed a sheath or bead applied in accordance with my invention positively prevents contamination of the cutting edge of la blade so that, if sterilized in the course of manufacture as is the present good practice, the user may have the assurance that the blade reaches him in aseptic condition thus relieving him of any possibility of face infection. The sheath not only protects the keen shaving edge of the blade from damage but also protects the fingers of the user so that he may remove the blade from its Wrapping and place it in the holder Without danger of cutting himself. This is particularly so when the bead is given a rounded contour, a condition which is noticeable when the blade is handled.

Further, the protective bead or sheath consti-i tutes a positive -indication that blades thusj'" equipped are new blades and not used blades since the sheath must be fully removed for use and cannot be restored when it has once been 4following description of several preferred ernbodiments thereof, selected for purposes of illustration and shown in the accompanying drawing,

in which;

Fig..1 is a plan view of a commercial safety razor blade, shown on an enlarged scale, las being provided with a protective bead of my invention;

Fig. 2. is a view in cross-section on the line 2 2 of Fig. 1,; Y

Fig. 3 is a fragmentary plan View on a still larger scale;

Fis. d is a sectional view corresponding to Fig. 2, showing part. of a blade provided with.

alternative form oi protecting sheath; and

Fig. 5 is a fragmentary view in cross-section shown on. the line b-d oi? Fig. 3.

The blade shown. in Fig. l is typical oi commercial safety razor blades now Widely distributed in the market. It has corner notches dening central elongated unsharpened portions il and an elongated centrally disposed aperture of conventional shape. It is sharpened upon its opposite longitudinal :edges it by symmetrical bevels ground in the body of the blade and showing bright steel inthe finished blade. The body it of the blade is usually protected by lacquer or an oxidized coating or both but as already explained this terminates at the line of bevel. As shown in Figs. 1-3 both cutting edges i3 of the blade are surrounded by a protecting sheath or bead id which in this case may be transparent gelatin of any attractive color harmonious with the rest of the blade surface.

The sheath or bead i4 may be applied to the blade by dipping its bevelled edge in a suitablel bath of viscous solution, such as gelatin. The liquid solution adheres rst to the dipped surface of the blade and then by capillary action or surface tension takes of itself a rounded contour completely surrounding and encasing the bevelled edge oi the blade and, when solidified, forming a continuous channelled-shaped bead extending from end to end of the cutting edge I3 and over the cutting edge to a substantial thickness. A gelatinous solution on the blade edge, when once dried and hardened, adheres securely to the steel of the blade as a transparent sheath and is not likely to be disturbed in any ordinary handling of the blade. it has sumcient strength of structure to protect the blade against mechanical damage. It is sufdciently exible to flex with the blade without cracking and it is sufficiently impervious to moisture to eliminate the danger of corrosion. On the other hand, it is very readily soluble in water and may be removed from the blade edge in a few seconds by being rinsed in Water.

In Figs. i, 2 and 3 the protecting sheath or bead i ii is shown asbeing substantially co-extensive 'in width with the bevelled edge it of the blade,

that is, the bead extends to the line of bevel and slightly beyond, overlapping the lacquered blade surface and leaving no break exposing bright metal. in Fig. d, however, a blade 2t is shown aasasso as provided with a continuous coating which includes the protective beads 2i in which theopposite cutting edges of the blade are embedded. The protected blade of Fig. 4 may be produced by dipping the whole blade as distinguished from dipping merely its bevelled edge as suggested in Figs. 1 3.

In applying the protective bead or sheath to the blades of Fiss. i and 5 it is necessary only to dip the edges of the blades while held vertically into a hot viscous or gelatinous solution. The depth of the dipping governs the amount of solution piclred up by the blade edge; While the blade is held vertically the solution tends to run down and form itself into a bead or sheath of slightly bulging cross-section.` In practice the thickness of the sheath should not substantially exceed the thickness o! the blade body and under such conditions the protected blades may be handled and Wrapped by automatic machinery as rapidly and conveniently as unprotected blades.

While I prefer that the protective sheath should be removed by rinsing the blade in the razor in water, the sheath may be made so soluble that it will be softened and detached from the blade edge by being merely applied to the lathered face of the user. A parailin sheath is softened and detached from the blade by the action of heat with or without moisture.

The present invention includes within its scopeA the novel process herein disclosed of protecting the sharp edges of blades by dipping the same or otherwise forming thereon a continuous solid sheath of soluble oreoftenable material from a viscous or gelatinous solution.

Having thus disclosed my invention and described certain preferred embodiments thereof I claim as new and desire to secure by Letters Patent:

1. A iexible razor blade having a ground bevel exposing the bright steel of the blade and presenting a sharp cutting edge and a protecting rounded bead of soluble transparent material enclosing the bright steel of Vthe blade and providing a flexible sheath protecting it against corrosion and its sharp edge against mechanical damage.

2. A thin exible safety razor blade harina a body of uniform thickness provided with a protective coating, and a bevelled cutting edge free of said coating and protected by an .adheridai fiexible rounded beadnormally rm in structure but capable of being readily detached from said cutting edge by the action 0i heat.

JOSEPH MUROS. 

